20261172547161 has 60 divisors (see below), whose sum is σ = 37916512661412. Its totient is φ = 10687211865792.

The previous prime is 20261172547159. The next prime is 20261172547163. The reversal of 20261172547161 is 16174527116202.

20261172547161 is a `hidden beast` number, since 2 + 0 + 2 + 6 + 1 + 172 + 5 + 471 + 6 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (20261172547159) and next prime (20261172547163).

It can be written as a sum of positive squares in 2 ways, for example, as 7266156927561 + 12995015619600 = 2695581^2 + 3604860^2 .

It is not a de Polignac number, because 20261172547161 - 2¹ = 20261172547159 is a prime.

It is a super-2 number, since 2×20261172547161² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20261172547163) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 196289010 + ... + 196392203.

Almost surely, 2^{20261172547161} is an apocalyptic number.

20261172547161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20261172547161 is a deficient number, since it is larger than the sum of its proper divisors (17655340114251).

20261172547161 is a wasteful number, since it uses less digits than its factorization.

20261172547161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392681252 (or 392681236 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 45.

The spelling of 20261172547161 in words is "twenty trillion, two hundred sixty-one billion, one hundred seventy-two million, five hundred forty-seven thousand, one hundred sixty-one".